IBM Thursday introduced four rack servers and one blade server using the Xeon 5300, with starting prices ranging from $2,400 to just over $3,000.

A quad-core processor has four independent processors combined into one package, which allows the chip to perform four tasks simultaneously. Quad-core processors give the computer greater processing power than if it had dual-core or single-core processors. IBM said its x3650 server with a quad-core processor recorded a 64 percent increase in performance compared to the same model running only a dual-core processor.

Quad-core technology makes it easier for IT managers to introduce virtualization into their datacenters. Virtualization lets enterprises make better use of server capacity by running multiple programs -- and even different operating systems -- on the same physical server at the same time. IBM's quad-core System x servers support virtualization through a feature called IBM Virtualization Manager, which lets administrators manage virtual and physical servers on any number of virtualization software platforms, including VMware, Microsoft Virtual Server and Xen.

The new x3550 and x3650 are available for order beginning Nov. 14, and the x3400, x3500 and BladeCenter HS21 will be available in January, IBM said.